Cs ₂ SnCl ₆ ‐Glass Composites for Highly Efficient Immobilization of Cs ⁺ in Chlorine‐Containing Molten Salts

ABSTRACT ¹³⁷ Cs has become one of the key challenges in the dry reprocessing of spent fuel due to its poor separability and high radioactivity. The synthesis of Cs ₂ SnCl ₆ for the removal of CsCl from waste salts and the preparation of Cs ₂ SnCl ₆ ‐glass composites was investigated in this study. The optimal conditions for the hydrothermal synthesis of Cs ₂ SnCl ₆ are a reaction at 150°C for 6 h, and XRD results indicate that the product is a pure cubic phase. CsCl is removed from LiCl‐KCl‐CsCl waste salts by the synthesis of Cs ₂ SnCl ₆ . This method enables efficient and selective separation of Cs ⁺ from waste salts with a Cs ⁺ content of 2.5–10 wt.%, achieving a removal efficiency of over 96%. The glass composites have a maximum embedding rate of 30 wt.%. Cs ⁺ and Cl ⁻ are uniformly distributed in the glass matrix, and the glass matrix exhibits good compatibility with Cs ₂ SnCl ₆ . The PCT test showed that the normalized leaching rates of Cs ⁺ and Cl ⁻ on the 28th day were as low as 1.6×10 ^{− 4} and 3.4×10 ^{− 4} g·m ^{− 2} ·d ^{− 1} , respectively, demonstrating that the Cs ₂ SnCl ₆ ‐glass composite exhibits excellent leaching resistance.